Guide for catheterism

ABSTRACT

A guide is used for the selective catheterism of anatomic structures and for placing therapeutic instruments.

This application is a National Stage Application of PCT/EP2009/051465,filed Feb. 9, 2009, which claims benefit of Ser. No. 08/151,170.1, filedFeb. 7, 2008 in the EPO, and which also claims benefit of Ser. No.08/161,434.9, filed Jul. 30, 2008 in the EPO and which applications areincorporated herein by reference. To the extent appropriate, a claim ofpriority is made to each of the above disclosed applications.

FIELD OF THE INVENTION

The present invention relates to the use of a guide for the selectivecatheterism of anatomic structures and for placing therapeuticinstruments.

BACKGROUND OF THE INVENTION

The passing of a flexible guide called “a guide wire” into the differentnatural conduits of the human body such as those present in thedigestive, hepato-pancreatic, urinary, genital, respiratory,cardiovascular systems is generally necessary for introducingtherapeutic instruments (“medical devices”) up to the site to betreated. The guide should therefore go through the different conduitswith an increasingly reduced width up to the site to be treated. In allthese conduits, obstacles may be present preventing proper navigation ofthe guide and not allowing easy access to said site to be treated. Theobstacles may be of different natures, either natural or not, and beformed, for example by the sinuous anatomy of the conduit, or be due tothe presence of tumors, calculi, foreign bodies, or further to thepresence of folds in the mucosa. In order to navigate in these sinuousand/or obstructed conduits, or to circumvent these obstacles, presentguides are provided with a flexible end. Indeed, when the guide isconfronted with one of these obstacles, it may be diverted and come toimpact or touch the walls of the natural conduit which may cause aninjury (edema) and/or with a deterioration of the guide making thecontinuation of the navigation more difficult. Further, the dimensionsof the guide, in particular those of its distal end, opposite to thetherapist, should allow navigation of the guide in very narrow conduits,the diameter of which decreases gradually as the guide progresses in thenatural routes to be explored.

Solutions have been proposed in the different documents of the state ofthe art such as the “Loop Tip Wire Guide” described in document WO2006/039217.

However, the solutions currently present do not allow total resolutionof these technical difficulties and therefore do not satisfy thetherapists.

SUMMARY OF THE INVENTION

With the present invention, it is possible to navigate in a network ofconduits, the diameter of which decreases gradually as the guideprogresses in the routes to be explored.

Complementarily, with the present invention, it is possible to avoidinjuries or contusions due to the sharp end of the guide, to mucosas andendothelial walls, and the navigation of the guide may be facilitated bymeans of the particular shape of its end.

According to the invention, a guide for catheterism is proposed, thebody of which is provided at its distal end with an appendage or anendpiece having a three-dimensional shape, preferably axisymmetricalaround the axis of revolution of said guide. This three-dimensionalshape may for example be ovoidal, spheroidal, ellipsoidal. Preferablythis shape does not have any edge or acute angle and in particular has aprofile perpendicular to the longitudinal axis which has aquasi-constant radius of curvature. By quasi-constant is meant avariation comprised between 50 to 200% and preferably between 75 and125%.

More particularly, the guide is characterized in that the appendage orendpiece has in the plane perpendicular to the longitudinal axis of saidguide body at least one dimension greater than the diameter of saidguide body. Preferably, at least one dimension and preferably onedimension in the plane perpendicular to the longitudinal axis and inparticular the maximum diameter of the appendage is significantlygreater than the diameter of the body of the guide.

By significantly is meant an increase by at least 20%, preferably 30%,preferably 50%, preferably 100%.

According to another alternative, the appendage has significantlygreater dimensions than the body of the guide both in the radial andaxial directions.

According to a particularly preferred embodiment, the appendage or theendpiece of the guide is detachable from the body of said guide. Thedissociation may advantageously occur actually within the human oranimal body, i.e. in situ, and preferably on the site to be treated. Forthis purpose, the presence of dissociation means are provided, whichwill allow the appendage or the endpiece to be detached or dissociatedfrom the body of said guide on command from the therapist.

Advantageously, dissociation means are provided in order to make theappendage detachable from the guide actually within the human or animalbody. This appendage may of course also be detachable outside the humanbody. As an example, the release of the appendage of the guide may beaccomplished by the action of dissociation means already present on theguide.

Dissociation of the appendage or of the endpiece results from voluntaryaction of the therapist and should not by any means take place suddenly.

Preferably, dissociation is carried out by a mechanical action oncommand from the therapist.

Means for controlling the dissociation means may also be provided andadvantageously allow detachment of the appendage or the endpiece as soonas the site to be treated is reached.

Preferably, the integrality of the appendage or endpiece is detachedfrom the guide so as to avoid the presence of abrasive or blunt portionswhich may act on the surrounding tissues and injure them.

The attachment of the detachable appendage or endpiece on the guide iscarried out preferentially by physico-chemical interactions.

By the terms of “physico-chemical interactions” are meant all theinteractions which allow adhesion of two identical or differentmaterials, such as electrostatic, steric, hydration interactions,capillary condensation, interaction due to covalent forces, interactiondue to Van der Waals forces, overlapping interactions, etc.(“Intermolecular & Surfaces” 2^(nd) edition, JACOB ISRAELACHVILI,Academic Press (1992). ISBN: 0-12-375181-0 and “Fundamentals ofadhesion”, LIENG-HUANG Lee. Plenum Press New York (1991). ISBN:0-306-43470-9).

Preferably, all mechanical interactions are therefore excluded.

Alternatively, the attachment of the appendage or endpiece on the bodyof the guide is carried out with a substance having adhesive properties.

Advantageously, the connection between the appendage or the endpiece andthe body of the guide is selected depending on the physico-chemicalproperties of the materials used for their respective manufacturing.

According to another particularly preferred embodiment, the material ofthe appendage or of the endpiece of the guide is advantageouslydeformable or extensible by deployment.

The material of the appendage or of the endpiece of the guide isadvantageously elastic.

According to another embodiment, it is possible to also contemplate thatthe appendage be not present on the guide before it is introduced intothe human body, it only appears in the human body for example by theaction of an inflatable membrane.

Alternatively, the material of the appendage or of the endpiece of theguide may not be deformable, this is in particular the case if theendpiece is detachable.

More particularly, this appendage may be made in a metal, organic (forexample polymeric, elastomeric), silica, ceramic or composite material.The appendage should be preferably be biocompatible (such as for exampleas described in the standard EN ISO 10993-1) and unaffected by thesurrounding medium.

Preferably, the material in which this appendage or this endpiece ismade has a heat expansion coefficient greater than that of the materialin which the guide is made.

This appendage may be solid, hollow or crossed by one or more orifices.

Its outer surface will preferably be treated in order to obtain a lowerfriction coefficient than the anatomic environment and therefore haveimproved roughness so as to allow and facilitate navigation.

The appendage may be made in the same materials as those used for makingthe guide.

Preferentially, the body of the guide is made with at least one of thefollowing materials: cellulose acetate, cellulose nitrated, silicon,polyethylene, high density polyethylene, polyethylene terephthalate,polyurethane, polytetrafluoro-ethylene, polyamide, polyester,polyorthoester, polyvinyl chloride, polypropylene,acrylonitrile-butadiene-styrene, polycarbonate, polyurethane, nylonsilicones, polyanhydride and other equivalents.

Preferentially, the appendage or the endpiece is made with at least oneof the following materials: cellulose acetate, cellulose nitrate,silicone, polyethylene, high density polyethylene, polyethyleneterephthalate, polyurethane, polytetrafluoro-ethylene, polyamide,polyester, polyorthoester, polyvinyl chloride, polypropylene,acrylonitrile-butadiene-styrene, polycarbonate, polyurethane, nylonsilicones, polyanhydride or other equivalents.

The present invention advantageously allows single use of the guide forcatheter.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring now to the drawings wherein like reference letters andnumerals indicate corresponding structure throughout the views:

FIG. 1 is a sectional view through an axis of revolution of a firstembodiment of an appendage at a distal end of a guide according to theprinciples of the present invention;

FIG. 2 is a sectional view through an axis of revolution of a secondembodiment of an appendage at a distal end of a guide according to theprinciples of the present invention;

FIG. 3 is a sectional view through an axis of revolution of a thirdembodiment of an appendage at a distal end of a guide according to theprinciples of the present invention;

FIG. 4 is a sectional view through an axis of revolution of a curvedfourth embodiment of an appendage at a distal end of a guide accordingto the principles of the present invention;

FIG. 5a is a sectional view through an axis of revolution of a fifthembodiment of an appendage at a distal end of a guide according to theprinciples of the present invention;

FIG. 5b is a sectional view through the axis of revolution showing theembodiment of FIG. 5a with the appendage inflated;

FIG. 6a is a sectional view through an axis of revolution of a sixthembodiment of an appendage at a distal end of a guide according to theprinciples of the present invention;

FIG. 6b is a sectional view through the axis of revolution showing theembodiment of FIG. 6a with the appendage extended;

FIG. 7a-7c are sectional views through the axis of revolution showingthe embodiment of FIG. 1 with a catheter and showing the steps inremoving the appendage; and

FIG. 8a-8c are sectional views through the axis of revolution showingthe embodiment of FIG. 1 showing the steps in removing the appendage.

DESCRIPTION OF SEVERAL PREFERRED EMBODIMENTS OF THE INVENTION

According to a first embodiment, the guide for catheterism is providedat its distal end with an appendage or endpiece having athree-dimensional shape, preferably axisymmetrical, around the axis ofrevolution of said guide.

Preferably, the guide is characterized in that the appendage or endpiecehas in the plane perpendicular to the longitudinal axis of said guide adimension greater than the diameter of said guide.

Preferably, the appendage of endpiece of the guide is firmly attached tothe body of said guide.

Alternatively, the appendage or the endpiece of the guide is detachablefrom the body of said guide.

Preferably, the material of the appendage or of the endpiece of theguide is deformable.

Alternatively, the material of the appendage or of the endpiece of theguide is not deformable.

FIGS. 1-4 each illustrate a preferential shape of the appendage presentat the distal end of the guide. These appendages have athree-dimensional shape and preferably are axisymmetrical around theaxis of revolution of the body of the guide. At least one dimension ispreferably a dimension in a plane perpendicular to the longitudinal axisand in particular a diameter and preferably the maximum diameter (φ₂) ofthe appendage 10 is significantly greater than the diameter (φ₁) of thebody 1 of the guide.

By significantly, is meant an increase by at least 20% preferably by atleast 50% and preferably by at least 100% of the maximum diameter (φ₂)of the appendage 10 relatively to the (constant (φ₁) diameter of thebody 1 of the guide.

In a first embodiment illustrated in FIG. 1, the appendage significantlyjuts out from the body 1 of the guide both in the axial direction (L₂)and in the radial direction (φ₂).

In other embodiments, more particularly illustrated in FIGS. 2 and 3, lthe dimension (maximal diameter φ₂) of the appendage only significantlyexceeds the diameter (φ₁) of the body of the guide 1 in the radialdirection. The dimension in the axial direction essentially correspondsto the distal tip of the body of the guide.

In another embodiment, more particularly illustrated in FIG. 4, theguide is curved, the axis of revolution of the appendage preferablybeing the axis 100 of the guide when the latter is straightened out(i.e. in the non-curved position).

In another embodiment as the one illustrated in FIG. 5, the appendage isdeformable or extensible allowing a change in shape and/or in volume,allowing a transition from a non-deployed state to a deployed state orvice versa, the deployed state being defined by the fact that at leastone dimension and in particular one dimension perpendicular to thelongitudinal axis, and preferably the diameter (φ₂) of the appendage, issignificantly greater than the diameter (φ₁) of the body of the guidewhile the non-deployed state corresponds to a state where the appendagedoes not have any dimension in the plane perpendicular to thelongitudinal axis, greater than the maximum dimension and in particularthan the diameter of the body of the guide.

In this particularly preferred embodiment of the invention, theappendage 10 is preferentially formed by an extensible or inflatableelement 11 such as a membrane or a balloon, which may be inflated by agas or a fluid 12.

In this case, the volume of the appendage 10 is for example obtained bysimply injecting a pressurized fluid through an internal channel 2present in the guide 1.

According to an embodiment illustrated in FIG. 6, the appendage 10 isextensible or deformable. By extensible, is meant a change in volume ofthe appendage while by deformable is meant a change in its shape.

Advantageously, the appendage may pass from a deployed state to anon-deployed state by modification of its shape and/or of its volume.The deployed state is defined by the fact that at least one dimensionand in particular one dimension perpendicular to the longitudinal axisof the body of the guide and preferably the maximum diameter of theappendage is significantly greater than the diameter of the volume ofthe guide while the non-deployed state corresponds to a state where theappendage does not have any dimension greater than the diameter of thebody of the guide.

According to another preferred embodiment, the appendage may be made ina shape memory material such as shape memory polymers which will modifytheir state or their shape by a rise in the temperature of the ambientmedium. This rise in temperature may quite simply occur by applicationof an external means such as an electric current or simply by theinfluence of the body temperature.

FIG. 7 illustrate the means for detaching or dissociating the appendage10 or the endpiece (detachable) from the body of the guide 1. Thedifferent steps (FIGS. 7a-7c ) required for detaching the appendage orthe endpiece from said means are illustrated therein.

The dissociation means illustrated in FIG. 7 are for example formed by acatheter 4 which exerts pressure on the outer face of the appendage 10or of the endpiece.

Preferably, the end of the catheter exerting this pressure comprises aring or circlet ensuring uniform distribution of the pressure on theappendage or the endpiece. Preferably, the presence of this ringincreases the stiffness of the end of the catheter.

FIG. 8 illustrate means for detaching or dissociating the appendage 10or the endpiece (detachable) from the guide body 1. The different steps(FIGS. 8a-8c ) required for detaching the appendage or the endpiece withsaid means are illustrated therein.

The firm attachment means illustrated in FIG. 8 are formed by aninternal conduit or channel 6 present inside the guide body 1 and one ofthe open ends of which coincides with the distal end, relatively to thetherapist, of the guide.

This conduit or channel 6 allows a pressurized fluid to be conveyed fromthe proximal end, relatively to the therapist, of the guide.

This fluid will exert sufficient pressure on the internal face of theappendage 10 or endpiece so as to cause its integral dissociation fromthe guide 1.

Preferably, this fluid is a liquid. Alternatively, this fluid is a gas.Preferably, this liquid is water. Alternatively, this liquid is a salinebuffer.

A device comprising both types of aforementioned means for detaching thedetachable appendage or endpiece from the guide is another preferredembodiment.

EXAMPLES 1. Selective Catheterism of the Biliary Route

Selective catheterism of the biliary route through the papilla of Vateris technically difficult and may be accomplished either directly with acatheter or with a guide. Oddi's sphincter is covered with a mucosa and,when catheterism is not successful during the first maneuvers, repeatedhandling of catheters or of a guide which impacts in the mucosa, createsan edema, making the procedure more difficult.

The type of guide described above, provided with an atraumatic androunded end, not having any angulation, allows reduction of the traumaof the mucosa and of the edema resulting from this. Also, it helps theflexible end of the guide to adapt to the S-shape of the papilla, inorder to find its way towards the biliary route.

Guides modified according to the present invention have been tested inanimal models. These tests have revealed that this particular embodimentof the present invention allows significant reduction in the tendency toimpaction of the distal end of the guide in a complex structure.

In order to be able to continue to use the guide, in narrower conduits,the appendage is voluntarily detached from the guide, inside the animalsby action of the catheter on the guide.

The appendage used for this catheterism is a shape similar to the oneillustrated in FIG. 2. This appendage is detached from the body of theguide by action of the dissociation means. The tested material formingthe appendage is polyester. The dimensions of appendage for this testare:

-   φ₁: diameter of the guide, at its flexible end.-   φ₁=0.035″ (0.889 mm) in this example.-   φ₂=maximum diameter of the appendage.-   φ₂=1.7 mm in this example.-   L₂: height of the appendage.-   L₂=2.5 mm in this example.

2. Selective Catheterism of the Pancreas

Selective catheterism of the pancreas is technically difficult and maybe accomplished either directly with a catheter, or with a guide. Oddi'ssphincter is covered with a mucosa and when the catheterism is notsuccessful during the first maneuvers, repeated handling of catheters ora guide which impacts in the mucosa, creates an edema, making theprocedure more difficult. The type of guide described above, providedwith an atraumatic and rounded end, not having any angulation, allowsreduction of the trauma at the mucosa and of the edema resulting fromthis. Also, it helps the flexible end of the guide to adapt to theS-shape of the papilla, in order to find its way towards the pancreas.

Guides modified according to the present invention have been tested inanimal models. These tests have revealed that this particular embodimentof the present invention allows significant reduction in the tendency toimpaction of the distal end of the guide in complex structures.

The appendage used for this catheterism is a spherical shape. The testedmaterial forming the appendage is polyester. The dimensions of theappendage for this test are:

-   φ₁: diameter of the guide, at its flexible end.-   φ₁=0.035″ (0.889 mm) in this example.-   φ₂=maximum diameter of the appendage.-   φ₂=1.5 mm in this example.-   L₂: height of the appendage.-   L₂=1 mm in this example.    Dimensions of the Appendage in the Case of Catheterism of the    Biliary Route and of the Pancreas:-   1.2φ₁<φ₂<3 mm-   0.5 mm<L₂<5 mm-   φ₂: diameter of the guide at its flexible end.-   φ₂: maximum diameter of the appendage.-   L₂: height of the appendage.

The invention claimed is:
 1. An assembly for catheterism, comprising: aguide for catheterism, having a proximal end and a distal end, anddefining a longitudinal axis, wherein the distal end of the guide isflexible; an appendage or endpiece attached to the distal end of theguide, the appendage or endpiece having a shape which is axisymmetricabout the longitudinal axis, wherein the appendage or endpiece comprisesa channel extending along the longitudinal axis; and a cathetercomprising an axial lumen configured for slidingly receiving the guide,wherein the axial lumen has a diameter smaller than a maximum diameterof the appendage or endpiece; wherein the distal end of the guidecomprises a portion having a continuous diameter, the portion extendingalong the longitudinal axis; wherein the portion having a continuousdiameter comprises a distal part adjacent the appendage or endpiece anda proximal part extending from the distal part towards the proximal endof the guide, wherein the channel receives the distal part of theportion having a continuous diameter, wherein the proximal part of theportion having a continuous diameter extends outwardly beyond thechannel and the axial lumen receives the proximal part of the portionhaving a continuous diameter; wherein a proximal surface of theappendage or endpiece around the channel engages a distal face of thecatheter and blocks movement of the catheter relative to the appendageor endpiece; wherein the appendage or endpiece is configured fordetaching from the guide within a human or animal body by exerting aforce oriented in a distal direction between the catheter and theappendage or endpiece to disengage the appendage or endpiece from thedistal end of the guide, wherein the flexible distal end of the guideprovides for continued atraumatic navigation through the human or animalbody when the appendage or endpiece is removed.
 2. The assembly of claim1, wherein the appendage or endpiece has a maximum diameter which is atleast 20% greater than a diameter of the guide at the distal end.
 3. Theassembly of claim 1, wherein the appendage or endpiece has a maximumdiameter which is at least 50% greater than a diameter of the guide atthe distal end.
 4. The assembly of claim 1, wherein the appendage orendpiece is attached in the channel to the distal part of the portionhaving a continuous diameter through physico-chemical interactions. 5.The assembly of claim 1, wherein the appendage or endpiece is attachedin the channel to the guide through adhesion between a wall of thechannel and a wall of the distal part of the portion having a continuousdiameter.
 6. The assembly of claim 1, wherein the guide comprises aninternal conduit which is open to the distal end of the guide, whereinthe internal conduit is configured for conveying a pressurized fluidfrom the proximal end to the distal end of the guide for exerting apressure on the channel of the appendage or endpiece for detaching theappendage or endpiece from the guide.
 7. The assembly of claim 1,wherein the appendage or endpiece has an ovoid shape.
 8. The assembly ofclaim 1, wherein the appendage or endpiece has a maximum diameter of 3mm.
 9. The assembly of claim 1, wherein the appendage or endpiece has amaximum diameter of 1.7 mm.
 10. The assembly of claim 1, wherein theappendage or endpiece has a height measured along the longitudinal axisof between 0.5 mm and 5 mm.
 11. The assembly of claim 1, wherein theappendage or endpiece has a height measured along the longitudinal axisof between 0.5 mm and 2.5 mm.
 12. The assembly of claim 1, wherein thedistal end of the guide has a diameter of 0.035 inches.
 13. The assemblyof claim 1, wherein the assembly is configured for catheterizing abiliary tract or a pancreatic tract.
 14. The assembly of claim 1,wherein the channel is a blind hole.
 15. An assembly for catheterism,comprising: a guide for catheterism having a proximal end and a distalend, and defining a longitudinal axis, wherein the distal end of theguide is flexible and comprises a first diameter; an appendage orendpiece attached on the distal end of the guide, the appendage orendpiece having a three-dimensional shape, the shape comprising a seconddiameter larger than the first diameter, wherein the appendage orendpiece comprises a channel extending along the longitudinal axis, anda catheter comprising an axial lumen configured for slidingly receivingthe guide, wherein the axial lumen has a diameter smaller than thesecond diameter; wherein the distal end of the guide comprises a portionhaving a continuous diameter, the portion comprising the first diameterand extending along the longitudinal axis, wherein the portion having acontinuous diameter comprises a distal part received in the channel anda proximal part extending from the distal part outward beyond thechannel towards the proximal end of the guide, wherein a proximalsurface of the appendage or endpiece around the channel facing thecatheter engages a distal face of the catheter and blocks movement ofthe catheter relative to the appendage or endpiece, and allows thedistal end of the guide to extend into the channel; wherein theappendage or endpiece is configured for detaching from the guide withina human or animal body by exerting a force oriented in a distaldirection between the catheter and the appendage or endpiece todisengage the appendage or endpiece from the distal end of the guide,such that the flexible distal end of the guide provides for continuedatraumatic navigation through the human or animal body when theappendage or endpiece is removed.
 16. The assembly of claim 15, whereinthe appendage or endpiece is attached in the channel to the distal partof the portion having a continuous diameter through physico-chemicalinteractions.
 17. The assembly of claim 1, wherein the continuousdiameter is a constant diameter.
 18. The assembly of claim 15, whereinthe continuous diameter is a constant diameter.
 19. The assembly ofclaim 15, wherein the three dimensional shape is an ovoid shape.